1. Field of the Invention
The present invention relates to apparatus for compressing material, for example straw or other crop material.
2. Description of the Prior Art
In a known baling machine for example for compressing and baling straw, a pick up rotor on a tractor drawn machine collects straw from the ground and the straw is transferred sideways across the machine by, for example, an auger into the input opening of a longitudinal compression chamber positioned along the length of the machine. The straw is periodically compressed by a reciprocating compression piston driven along the compression chamber, straw being fed into the chamber transversely, at right angles to the direction of travel of the piston. There is no end door to the compression chamber for the compression piston to bear against, the compression of straw taking place instead by virture of the resistance to the movement of the straw along the compression chamber. The walls of the compression chamber are slightly converging in the direction of compression, or alternatively the side walls of the compression chamber may be parallel and there may be provided compression plates at the top and bottom of the chamber which are arranged to converge towards each other. Periodically, measured lengths of the column of compressed straw are tied with two or more strands of twine to form bales.
The form of compressor baler described above has a number of limitations. For example the density of compression which can be achieved is relatively low due to the fact that there is no end plate for the compression piston to bear against. Also it is difficult to obtain uniform compression due to variations in the moisture or other qualities of the straw and hence variations in the friction between the straw and the walls resulting in varying resistance offered to the compression piston.
Furthermore, it is not possible to have a truly continuous input of material for compression because the material is fed into the side of the compression chamber at right angles to the direction of compression of the piston. The input cannot be truly continuous because no input can pass into the chamber during a compression stroke.
According to the present invention there is provided a compression apparatus including a press framework defining a compression region for housing material to be compressed, one or more compression elements for compressing material by movement along the compression region, and a drive mechanism for moving the compression element or elements in a cycle of movement having one stage in which the or each element enters into the compression region, a further stage in which the or each compression element is moved along the compression region along a substantially rectilinear path to compress material in the compression region, and a yet further stage in which the or each compression element is returned to the position it occupied at the beginning of the first mentioned stage, the compression element or elements being at least partially removed from the compression region during the return movement in the last mentioned stage.
By the term press framework is meant a structure which houses the material during compression and restrains the material sufficiently to allow compression to take place during movement of the compression elements along the framework. Thus the framework may consist of a relatively open framework having floor members sufficient to support the material during compression, and side members sufficient to restrain the material during compression. In some examples an upper part of the framework may be open allowing some upward movement of the material during compression.
However it will be appreciated that in some arrangements the press framework may comprise a bale chamber or conduit having one or more continuous walls. Conveniently one or more such walls may have slots suitable to accommodate the entry of the compression element or elements.
The press framework may have an input opening for receiving material to be compressed and at the other end thereof an end stop member positioned for the compression element or elements to compress the material against, the end stop member being openable or removable after compression of the material to allow removal of the compressed material from the compression region.
The press framework may have at one end an input opening for receiving material to be compressed, and the input opening may be arranged to receive material into the compression region by movement of the material along the same general direction as the movement of the compression element or elements during compression of the material.
Preferably there are provided mechanism for shaping the material to be compressed into a preformed column of material and for feeding the preformed column of material into the compression region, and the compression element or elements may be arranged during the last mentioned stage to execute the return movement by moving past the preformed column of material during its movement into the compression region.
Furthermore there may be provided a mechanism for shaping the material to be compressed into a preformed column of material and for feeding continuously the preformed column of material into the compression region, the drive mechanism being arranged to move the compression element or elements into a position between a main body of the column of material entering into the compression region and a portion of the column of material within the compression region, the compression element or elements being arranged during the further stage to compress the portion of material in the compression region while the main body of material continues to enter the compression region.
In some preferred arrangements of the invention the compression element or elements are adapted to sever the portion of material to be compressed from the main body of material.
The drive mechanism may include a mounting member for moving the compression element or elements into and out of the compression region by a movement of the compression element or elements transverse to the direction of movement of the compression element or elements during the further stage when the material is being compressed in the compression region. The transverse movement may be in a direction substantially at right angles to the direction of movement of the compression element or elements during the further stage of the cycle when the material is being compressed.
Preferably, the drive mechanism includes a pivotal mounting assembly for moving the compression element or elements into and out of the compression region by a pivotal movement of the compression element or elements.
Conveniently the compression element or elements are mounted by a mounting assembly positioned externally of the compression region.
Conveniently the end stop member comprises an end door pivoted along a horizontal axis substantially at the level of the roof of the press framework and secured in place by a catch mechanism substantially at the level of the floor of the press framework. Alternatively the end stop member may comprise two half width doors pivoted horizontally top and bottom, or two vertical doors pivoted at the sides thereof.
In some arrangements it may be preferable for the drive mechanism to be coupled directly between the end stop member and the compression element or elements during compression of the material. In this way the compressive forces can be applied directly between the end stop member and the compression element or elements and if desired the end stop member may be allowed some degree of movement relative to the rest of the press framework. In some cases the end door or doors can conveniently be coupled directly to the drive machanism in such a manner that the doors are secured in a closed position during compression by the forces exerted on the compression elements to effect the compression.
There may be provided a pressure sensitive switch in the region of the end door of the press framework which is sensitive to contact by the material to be compressed, the movement of the compression elements being initiated in response to a signal from the pressure sensitive switch.
There may also be provided in the region of the end of the press framework remote from the input opening one or more roof members in the upper part of the compression region which is or are movable between a lower and an upper position, the or each roof member being arranged to be in the lower position when the door is shut, and to be movable to the upper position when the door is opened after complete compression of material so as to allow partial expansion of the compressed material to facilitate ejection of the compressed bale from the compression region.
The compression element or elements may be mounted on a subframe positioned externally of the compression region, the subframe being mounted for substantially rectilinear movement relative to the compression region to effect the said movement of the compression element or elements along the compression region during the further stage of the cycle. The subframe may comprise a yoke extending around the compression region.
Conveniently the subframe may be mounted on tracks running along opposed sides of the compression region on the outside thereof. The drive mechanism may include a pair of hydraulic rams positioned one on each side of the compression region and coupled between the subframe and an end door or other end stop mechanism against which the material is to be compressed. As has been mentioned before the drive mechanism may be coupled indirectly to the end door (or other stop member) by being coupled to the press framework to which in turn the end door (or other stop member) is coupled. Alternatively the drive mechanism may be coupled directly to the end door (or other stop member) in such a manner that the tension forces applied to compress the material act directly between the compression elements and the end door (or other stop member). The coupling may be arranged in such a manner that the forces applied to compress the material also act to secure the end door (or other end stop member) in a closed position.
There may be provided control mechanism along the press framework which engage the compression element or elements on advance of the subframe during the further stage of the cycle, the engagement of the compression element or elements with the control mechanism being such as to force the compression element or elements inwardly towards the compression region.
In embodiments of the invention it is preferred that the drive mechanism includes support member on each of two opposed sides of the compression region for applying force to the compression element or elements for driving the element or elements along the compression region during the compression of material. The support member on each side of the compression region may have the function of driving one or more compression elements which span the compression region between the two opposed sides, or may have the function of driving two oppositely facing arrays of cantilevered compression elements.
Thus in some preferred arrangements at least one compression element is positioned on each of two opposed sides of the compression region. Preferably a plurality of compression elements is provided, arranged in two oppositely facing arrays extending into the compression region during the further stage of the cycle.
It will be appreciated that the cycle of movement of the compression element or elements may include further stages in addition to the three stages set out above. For example the drive mechanism may move the compression element or elements in a preliminary stage so that the compression element or elements being to move along a general longitudinal direction of the press framework before the one stage in which the or each element enters into the compression region.
The compression element or elements may during the last mentioned stage of the cycle be totally withdrawn from the compression region by action of the drive mechanism, or the compression element or elements may be moved along the return movement by the drive means and may be removed from the compression region merely by the effect of further material to be compressed entering the compression region while the compression elements are on the return stroke so that the compression element or elements are forced outwardly from the compression region by the incoming material to be compressed. In such a case the compression element or elements may be only partially withdrawn from the compression region and may to some small extent extend into the incoming crop during the relative movement between the crop and the compression elements on their return stroke.